Maa Sita is an incarnation of Goddess Lakshmi and she taking form of Kali clearly tells that all mothers are form of the same Adi Shakti.

 

In the Mahakala Samhita , Kamakala Kali Khand 10 th Patal ; it is mentioned that Once King Ravana had to fight a battle against Asuras of "Kalakeya Clan" who were the future generations of Demon Hiranakashya. Before going for the Battle King Ravana worshipped Maa Kamakala Kali. It is stated in the text that Ravana wrote a Strotam to worship Maa Kamakala Kali.

In the Adhbut Ramayana' Sage Valmiki writes how Maa Sita took the form of Goddess Kali. When Sri Rama killed Ravana, and the news was sent to Maa Sita, she laughed and said it took so many years for Sri Rama to kill ten headed Ravana. How many years will he take to kill his brother Sahastra Ravana (the thousand headed Ravana who was brother of ten headed Ravana). Sahastra Ravana was much more powerful than his ten headed brother Ravana. Thereafter Maa Sita took form of Mahakali and killed Sahastra Ravana.

Maa Sita is an incarnation of Goddess Lakshmi and she taking form of Kali clearly tells that all mothers are form of the same Adi Shakti. The mother has three forms : the creator (Saraswati), the preserver (Lakshmi) and the destroyer (Kali). When she nurtures she is compassionate and when she kills she is wrathful. She is gunateeta (beyond gunas) that is beyond all three gunas (satva guna, raja guna and tamo guna) and at the same time takes form related to one guna when needed.

Jai Maa Kali!